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    Proteus- Timestep Too Small error Message

    All,

    I am unable to run my simulation using Proteus software. It pops out ''timestep too small error message'' Can anyone help on how to proceed resolve this?

    Please find the attached file below. Could anything be wrong with the design? The driver works well when run separately. Please help.

    Thanks,
    Ibrahim.Attached file.zip

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    Re: Proteus- Timestep Too Small error Message

    * Did you try various timesteps? Higher? Lower?

    * There may be some transient event which is only incidental to circuit operation, yet which takes up the simulator's time as it tries to resolve it. If you try a faster timestep, the simulator may ignore it more easily.

    * Do you have diodes and coils next to each other? At low current flow they might alternately conduct, in oscillation. It can help to put a resistor across the ends of a coil or diode, or from one end to a supply rail.

    * A simulator does not always like two capacitors in series, or a capacitor across a power supply. Try installing a resistor inline with a capacitor.


    1 members found this post helpful.

    •   Alt10th December 2013, 15:47

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    Re: Proteus- Timestep Too Small error Message

    Add to this list, logic circuits built with ideal transistors
    and not reasonable parasitic capacitances. Insane edge
    rates result. Make sure whatever you're driving has sane
    series resistances and shunt capacitances.


    1 members found this post helpful.

    •   Alt10th December 2013, 19:44

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  4. #4
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    Re: Proteus- Timestep Too Small error Message

    Quote Originally Posted by dick_freebird View Post
    Add to this list, logic circuits built with ideal transistors
    and not reasonable parasitic capacitances. Insane edge
    rates result. Make sure whatever you're driving has sane
    series resistances and shunt capacitances.
    BradtheRad/Dick,

    The timestep too small error message has been resolved by installing 1k Ohms between gate and source. The voltages and current measured are as calculated but wave form not looking good- very high oscillation. From the Oscilloscope, the inductor current is oscillating. Find the attached snapshot below.

    Please, can you assist me to look at the design for any design error?

    I ejectected Positive PULSE GENERATOR AT Q1&Q3 and negative at Q2&Q4

    Thanks,
    Ibrahim.



    •   Alt12th December 2013, 12:09

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  5. #5
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    Re: Proteus- Timestep Too Small error Message

    Sorry, your files are in a proprietary format. I find two files but I do not have any program that can read them. (Nor could I read your post #1 attachments.)

    Can you take screenshots of your images, and attach them as graphics files?

    The voltages and current measured are as calculated but wave form not looking good- very high oscillation. From the Oscilloscope, the inductor current is oscillating.
    * This suggests ringing in your coil. Is there a capacitor close to it? Creating resonant action?

    * A coil generates its own current for a brief time after you shut off its current flow. This can result in high voltage spikes, particularly if it suddenly sees high impedance.



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    Re: Proteus- Timestep Too Small error Message

    Quote Originally Posted by BradtheRad View Post
    Sorry, your files are in a proprietary format. I find two files but I do not have any program that can read them. (Nor could I read your post #1 attachments.)

    Can you take screenshots of your images, and attach them as graphics files?



    * This suggests ringing in your coil. Is there a capacitor close to it? Creating resonant action?

    * A coil generates its own current for a brief time after you shut off its current flow. This can result in high voltage spikes, particularly if it suddenly sees high impedance.


    BradtheRad,

    Please find attached pdf copy below.

    How can ringing in a coil be eliminated? I do not have capacitor close to the coil.

    Thanks.
    Last edited by Ogbachi; 12th December 2013 at 15:45.



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    Re: Proteus- Timestep Too Small error Message

    R11 is unclear. It looks as though it is 1 ohm across a power supply.

    Q1 gate does not appear to be connected to anything.

    Q1 and Q3 may need to have gate voltage increased, in order to turn them on.



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    Re: Proteus- Timestep Too Small error Message

    Quote Originally Posted by BradtheRad View Post
    R11 is unclear. It looks as though it is 1 ohm across a power supply.

    Q1 gate does not appear to be connected to anything.

    Q1 and Q3 may need to have gate voltage increased, in order to turn them on.


    BradtheRad,

    Many thanks on your response. R11 is 1.0 Ohms, is anything wrong with selection?

    You are right, Q1 gate was not connected but when it was connected it did not change the previous result.

    Can you assist me to look at the coupled inductor connection if that is the proper connection?

    Thanks,
    Ibrahim.



  9. #9
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    Re: Proteus- Timestep Too Small error Message

    Every real inductor has series resistance; add some as
    a component if your inductor primitive has no Rs term.
    Similarly every real capacitor has Rs. When you have
    a square voltage step, somebody had best prevent an
    infinite current spike or a ring-up that is so fast that
    you step right past a bistable point instead of through
    it, orderly. This is how binary-search solvers get lost
    and can't recover, because backward != forward.



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